System for managing glucose levels in patients with diabetes or hyperglycemia

This invention relates to maintenance of proper glucose levels in hyperglycemic individuals, and in particular, to a system that aids in the correct administration of insulin through the use of computerized insulin dosage calculations that are made with the use of individual-specific information.

Maintaining proper blood sugar, i.e., glucose, levels is important for hyperglycemic individuals, e.g., diabetics, in order to prevent long term problems such as nerve damage, blindness, and kidney disease. The need to control blood glucose (often referred to as BG) levels is even more important with hyperglycemic patients in critical care situations, such as in hospital intensive care units following surgical procedures, as those patients are more likely to suffer adverse physical effects, e.g., infections, from improperly maintained BG levels. Compounding this problem is the fact that BG levels in such patients may be unstable, necessitating frequent measurements and adjustments of administered insulin dosage. At times the degree of insulin dosage adjustment may be significant, or the calculated dosage amount may be high, so that it is difficult to determine whether the calculated insulin dose is correct or if an error in blood sugar measurement or an equipment malfunction has occurred.

It is therefore an object of one embodiment of the present invention to provide a system for monitoring patients\' blood glucose levels, calculating proper insulin dosages, and providing relevant feedback information and messages to the individual, or when used in a hospital or other in-patient setting, to the patient\'s physician, nurse, or other caregiver. Variations of BG levels outside a predetermined range results in more frequent BG measurements, while calculated insulin doses that fall outside normally expected levels (either high or low) generate feedback messages and warnings that require additional measurement or caregiver intervention to insure the correct treatment is administered.

For the purposes of promoting understanding of the principles of the invention, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is hereby intended and alterations and modifications in the devices, systems and representations illustrated in the Figures of the drawing, and further applications of the principles of the present invention as illustrated herein being contemplated as would normally occur to one skilled in the art to which the invention relates.

Referring to FIG. 1, there is shown a blood glucose (BG) management system 10 for a hyperglycemic patient 12 who is illustratively being cared for in a hospital critical care setting, e.g., within an intensive care unit following heart surgery, although other patient settings are of course possible. The condition of patient 12 on bed 14 is shown as being illustratively monitored directly by a nurse or caregiver 16, but at least some functions that are performed by nurse 16 could be performed by automatic monitoring (pulse, blood pressure), data entry, and/or intravenous medication delivery equipment (not shown), to name only a few possible examples. For purposes of explaining an embodiment of the present invention, patient 12 is shown as receiving a continuous drip of insulin from reservoir 18 that is controlled by drip regulator 20 through an intravenous (IV) line 22.

In operation, nurse 16 tests the blood sugar or glucose level of patient 12 by a known, available means including, but not limited to, a traditional finger stick using known, commercially available products. Nurse 16 then enters the measured BG level of patient 12 into data handling device 24. Device 24 is illustratively shown as having a display 26 and an input 28. Display 26 may be of any conventional or available display type, such as, for example, a CRT or LCD screen, while input 26 may be a computer keyboard, for example. When the patient\'s measured glucose level has been entered into device 24, the entered information is sent via communications channel 30 to computer or data processor 32 which may be located at a central location, such as a nurses\' station or hospital-wide patient monitor center. Communications channel 30 may be of the form of a hardwired connection, a local area network, or an internet-based wide area network, to cite a few non-limiting examples. Network access may advantageously provide access to patient data from other hospitals or in-patient facilities, and it can allow patent 12 to be moved within a networked facility or between network-linked facilities, while still maintaining active monitoring of the patient\'s condition and providing access to historical patient data. Data processor 32 illustratively comprises a central processing unit (CPU) 34 and memory 36, which may be of any known or available form, such as, for example, ROM, PROM, RAM, EPROM or EEPROM. Also shown as being connected or associated with data processor 32 are display 38 (such as, for example, a CRT or LCD screen) and input device 40, such as a keyboard, for example.

Data processor 32 evaluates the BG level of patient 12 to determine if the glucose level is high or low. If it is low, data processor 32 calculates an appropriate dosage of glucose, typically administered as dextrose (such as that identified as D-50), that is needed to bring the BG level of patient 12 back within a predetermined “normal” range. If the BG level is high, data processor 32 calculates a proper insulin drip level that required to restore the BG level of patient 12 to the “normal” range. If the BG level is within the “normal” range for patient 12, data processor 32 calculates a proper insulin drip level sufficient to maintain the BG level of patient 12 within the “normal” range. The information is sent back to device 24 via communications channel 30 where it appears on display 26. Nurse or caregiver 16 then administers dextrose, if needed, or makes any necessary adjustments to drip regulator 20 so that the proper amount of insulin 18 is delivered to patient 12. The calculation used by CPU 34 of data processor 32 illustratively utilizes a known algorithm identified as the Protocol of Bode et al., and described in an article entitled “Intravenous Insulin Infusion Therapy: Indications, Methods, and Transition to Subcutaneous Insulin Therapy,” Endocrine Practice, Vol. 10 (Suppl. 2), March/April 2004, but a proprietary algorithm or some other proven calculation could be developed or adapted to be suitable as well.

FIG. 2 illustrates a flowchart which shows a BG management process 41 in accordance with an embodiment of the present invention, which will be used to illustrate the manner in which BG management system 10 of FIG. 1 operates. Beginning at step 42 of process 41, a particular patient is selected for BG monitoring or management by system 10. For illustrative purposes, the process of step 42 selects critical care patient 12. Step 44 determines from information provided by step 42 whether patient 12 requires a new insulin drip to be established, or whether a previously established insulin drip is to be restarted. If the drip is to be restarted, information concerning the previous insulin drip for patient 12 is retrieved from database 46 and used in step 48 to set initial insulin administration, e.g., drip rate, multiplier and “normal” BG level, data for patient 12. Having access to known information specific to patient 12 greatly aids in establishing an initial insulin drip rate that will be more accurate, and hence lead to a quicker stabilization of the BG level for patient 12 than would be possible if a drip rate were started from a nominal average value. Access to this information allows patient 12 to be temporarily discontinued from a drip without requiring a “break-in” period when the drip is resumed. If patient 12 is a new patient, or if information related to a previous drip is no longer valid, certain initial parameters, such as high and low target BG levels that establish a “normal” range for patient 12, are set and stored in database 46. Process 41 then proceeds to step 50, which measures the BG level of patient 12. In FIG. 1, the BG level of patient 12 is measured manually by nurse 14, and entered into data handling device 24, which communicates that information to data processor 32. Process 41, including step 50, need not be performed manually by a nurse or caregiver, but could be performed automatically without human intervention. The measured BG level is then evaluated at step 52 to determine if the BG level falls below, within, or above the “normal” range previously established for patient 12.